/dev/dsk/c3t2d1s0 is part of active ZFS pool vsm_pool1_1T. Please see
zpool(1M).

Anybody has an idea of what is going wrong here. It doesn't seem to
matter which of the drives I want to use for the new zpool, I am always
getting this error message - ven when trying only mirror c3t1d4 c3t1d3
or mirror c3t1d2 c3t1d1 alone.